1. Field of the Invention
The present invention relates to a stacked-plate type heat exchanger and in particular to a heat exchanger of the type for use in a refrigerator in which helium is used as refrigerant.
2. Description of the Related Art
In FIG. 5, there is illustrated a conventional stacked-plate type heat exchanger disclosed in Japanese Utility Model Publication No. 63-50618. This conventional heat exchanger includes plural plates 1 each of which is provided therein with a plurality of holes 3. Each plate 1 is made of a material having a high thermal conductivity, such as aluminum. Between two adjacent plates 1, a spacer 2 is interposed which is made of a material having a low thermal conductivity such as plastic. With respect to spacers 2, which are in alignment in the vertical direction, plural passages through which hot fluid or gas A flows and plural passages through which cold fluid or gas B flows are defined at a left side and a right side, respectively. In this heat exchanger, at each plate 1, heat exchange is performed between hot fluid A and cold fluid B.
In the above-mentioned heat exchanger, plural passages of one plate are in alignment with those of the adjacent plate. Due to this construction, each fluid or gas does not necessarily flow along or across the overall surface of each plate. In view of the roughness of the surface of each plate, as a whole, the efficiency in heat exchanging is not very good in addition to a loss of pressure.